• The Plant Pathology Journal
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• v.27 no.1
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• pp.20-25
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• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.321-327
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• 2010

We performed diagnostic PCR assays and a phylogenetic analysis using partial sequences of TEF1 (translation elongation factor-1) to determine the trichothecene chemotypes and genetic diversity of F. graminearum isolates from maize and rice samples collected in 2009 in Korea. PCR using a species-specific primer set revealed a total of 324 isolates belonging to the putative F. graminearum species complex. PCR with trichothecene chemotypespecific primers revealed that the nivalenol (NIV) chemotype was predominant among the fungal isolates from rice (95%) in all provinces examined. In contrast, the predominant chemotype among the corn isolates varied according to region. The deoxynivalenol (DON) chemotype was found more frequently (66%) than the NIV chemotype in Gangwon Province, whereas the NIV chemotype (70%) was predominant in Chungbuk Province. Phylogenetic analysis showed that all DON isolates examined were clustered into lineage 7, while the NIV isolates resided within lineage 6 (F. asiaticum). Compared with previous studies, the lineage 6 isolates in rice have been predominantly maintained in southern provinces, while the dominance of lineage 7 in maize has been evident in Gangwon at a slightly reduced level.

• The Plant Pathology Journal
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• v.37 no.3
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• pp.205-214
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• 2021

The use of the supernatant from a Bacillus subtilis culture mixed with sodium bicarbonate was explored as a means of controlling stem brown spot disease in dragon fruit plants. In in vitro experiments, the B. subtilis supernatant used with sodium bicarbonate showed a strong inhibition effect on the growth of the fungus, Neoscytalidium dimidiatum, the agent causing stem brown spot disease and was notably effective in preventing fungal invasion of dragon fruit plant. This combination not only directly suppressed the growth of N. dimidiatum, but also indirectly affected the development of the disease by eliciting the dragon-fruit plant's defense response. Substantial levels of the pathogenesis-related proteins, chitinase and glucanase, and the phenylpropanoid biosynthetic pathway enzymes, peroxidase and phenyl alanine ammonia-lyase, were triggered. Significant lignin deposition was also detected in treated cladodes of injured dragon fruit plants in in vivo experiments. In summary, B. subtilis supernatant combined with sodium bicarbonate protected dragon fruit plant loss through stem brown spot disease during plant development in the field through pathogenic fungal inhibition and the induction of defense response mechanisms.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.208-214
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• 2014

Wild rice, Oryza grandiglumis shows hyper-resistance response to pathogen infection. In order to identify genes necessary for defense response in plants, we have carried out a subtractive hybridization coupled with a cDNA macroarray. An acidic PATHOGENESIS-RELATED1 (PR1) gene of the wild rice is highly identical to the acidic PR1 genes of different plant species. The OgPR1a cDNA has an apparent single open reading frame with a predicted molecular mass 40,621 Da and an isoelectic point of 5.14. Both in silico analysis and a transient expression assay in onion epidermal cells revealed that the OgPR1a protein could be localized in intercellular space in plants. The OgPR1a mRNA was strongly transcribed by the exogenous treatment with ethylene and jasmonic acid as well as protein phosphatase inhibitors. Additionally, ectopic expression of the OgPR1a conferred disease resistance on Arabidopsis to the bacterial and fungal infections.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.386-393
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• 2010

In order to study disease resistance mechanisms in rice against the rice blast fungus Magnaporthe grisea, we screened fungal elicitor-responsive genes from rice suspension-cultured cells treated with fungal elicitors employing differential hybridization (DH). By DH screening, 31 distinct rice clones were isolated and a majority of them were full-length cDNAs encoding pathogenesisrelated (PR) genes. Sixteen of the 31 genes were upregulated at 4, 8, and 12 h following fungal elicitor treatment. To elucidate the effect of signal molecules and biotic elicitors on the regulation of rice defense genes, we further characterized the transcriptional expression patterns of representative isolated PR genes; OsGlu1, OsGlu2, OsTLP, OsRLK, and OsPR-10, following treatment with fungal elicitor, phytohormones, cycloheximide, and inhibitors of protein phosphorylation. Jasmonic acid (JA) induced transcriptional expression of OsGlu1, OsTLP, and OsRLK, but not of OsGlu2 and OsPR-10 at any of the tested time points. Salicylic acid (SA) and abscisic acid weakly induced the expression of OsTLP and OsRLK. SA showed an antagonistic effect with fungal elicitor and JA. Cycloheximide suppressed all these genes upon elicitor treatment, except for OsGlu2. Staurosporine only induced the expression of OsRLK. Application of calyculin A strongly induced OsRLK expression, but suppressed the expression of OsGlu2. Our study yielded a number of PR genes that play a role in defense mechanisms against the rice blast fungus, as well as contribute towards the elucidation of crosstalk between phytohormones and other modifications during defense signaling.

• Journal of Chest Surgery
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• v.19 no.2
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• pp.259-264
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• 1986

Broncholithiasis is defined as a cor9ition in which a concretion is present within a bronchus or a cavity in the lung communicating with a bronchus. The usual causes of broncholithiasis are known as tuberculosis, histoplasmosis, silicosis, aspirated calculi, and a few fungal infections. It is generally accepted that the constant motion created by respiration and beating of the heart may cause the peribronchial calcified lymph node to erode into the tracheobronchial tree and to form broncholith. After the analysis of our 6 cases of broncholithiasis which were treated surgically in the Department of Thoracic Surgery, Seoul National University Hospital from 1960 to December, 1985, we could suggest that intrinsic formation of calculi should be regarded as the pathogenesis of broncholithiasis in addition to the extrinsic formation of calculi.

• Pediatric Infection and Vaccine
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• v.18 no.1
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• pp.15-22
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• 2011

Invasive Candida infections (ICI) have become the third most common cause of late-onset infection among premature infants in the neonatal intensive care unit (NICU). Risk factors include birth weight less than 1,000 g, exposure to more than two antimicrobials, third generation cephalosporin exposure, parenteral nutrition including lipid emulsion, central venous catheter, and abdominal surgery. Candida colonization of the skin and gastrointestinal tract is an important first step in the pathogenesis of invasive disease. Strict infection control measures against the infection should be done in the NICU. The following practices are likely to contribute to reducing the rate of ICI: (1) restriction of broad-spectrum antibiotics, antacids and steroid; (2) introduction of early feeding and promoting breast milk. Fluconazole prophylaxis may be an effective control measure to prevent Candida colonization and infections in individual units with high incidence of fungal infection. In addition, there is a need of further data including the development of resistant strains and the effect on long-term neurodevelopmental outcomes of infants exposed to drugs before the initiation of routine application of antifungal prophylaxis in the NICU.

• Journal of Veterinary Clinics
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• v.12 no.1
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• pp.853-860
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• 1995

Two cases of guttural pouch mycosis in race horses were observed for clinical and pathological aspects of the disease to investigate etiology and pathogenesis of dysphagia and epistaxis of the horse. In case 1 showing prolonged dysphagic sign a diphtheritic membrane was confined to the guttural pouch involved with neuritis of the glossopharyngeal nerve due to fungal penetration. The other horse showing fatal recurrent epistaxis had lesion of mycetoma invading the internal carotid artery to provoke erosion of the artery. An Aspergillosis sp. was isolated from the guttural pouches of the two horses and identified as A nidulans.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.108-114
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• 2015

Curvularia lunata is an important maize foliar fungal pathogen that distributes widely in maize growing area in China, and several key pathogenic factors have been isolated. An yeast two-hybrid (Y2H) library is a very useful platform to further unravel novel pathogenic factors in C. lunata. To construct a high-quality full length-expression cDNA library from the C. lunata for application to pathogenesis-related protein-protein interaction screening, total RNA was extracted. The SMART (Switching Mechanism At 5' end of the RNA Transcript) technique was used for cDNA synthesis. Double-stranded cDNA was ligated into the pGADT7-Rec vector with Herring Testes Carrier DNA using homologous recombination method. The ligation mixture was transformed into competent yeast AH109 cells to construct the primary cDNA library. Eventually, a high qualitative library was successfully established according to an evaluation on quality. The transformation efficiency was about $6.39{\times}10^5$ transformants/$3{\mu}g$ pGADT7-Rec. The titer of the primary cDNA library was $2.5{\times}10^8cfu/mL$. The numbers for the cDNA library was $2.46{\times}10^5$. Randomly picked clones show that the recombination rate was 88.24%. Gel electrophoresis results indicated that the fragments ranged from 0.4 kb to 3.0 kb. Melanin synthesis protein Brn1 (1,3,8-hydroxynaphthalene reductase) was used as a "bait" to test the sufficiency of the Y2H library. As a result, a cDNA clone encoding VelB protein that was known to be involved in the regulation of diverse cellular processes, including control of secondary metabolism containing melanin and toxin production in many filamentous fungi was identified. Further study on the exact role of the VelB gene is underway.

• The Plant Pathology Journal
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• v.33 no.4
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• pp.402-409
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• 2017

Cyclic dipeptides (CDPs) are one of the simplest compounds produced by living organisms. Plant-growth promoting rhizobacteria (PGPRs) also produce CDPs that can induce disease resistance. Bacillus vallismortis strain BS07 producing various CDPs has been evaluated as a potential biocontrol agent against multiple plant pathogens in chili pepper. However, plant signal pathway triggered by CDPs has not been fully elucidated yet. Here we introduce four CDPs, cyclo(Gly-L-Pro) previously identified from Aspergillus sp., and cyclo(L-Ala-L-Ile), cyclo(L-Ala-L-Leu), and cyclo(L-Leu-L-Pro) identified from B. vallismortis BS07, which induce disease resistance in Arabidopsis against Pseudomonas syringae infection. The CDPs do not directly inhibit fungal and oomycete growth in vitro. These CDPs require PHYTOALEXIN DEFICIENT4, SALICYLIC ACID INDUCTION DEFICIENT2, and NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 important for salicylic acid-dependent defense to induce resistance. On the other hand, regulators involved in jasmonate-dependent event, such as ETHYLENE RECEPTOR1, JASMONATE RESPONSE1, and JASMONATE INSENSITIVE1, are necessary to the CDP-induced resistance. Furthermore, treatment of these CDPs primes Arabidopsis plants to rapidly express PATHOGENESIS-RELATED PROTEIN4 at early infection phase. Taken together, we propose that these CDPs from PGPR strains accelerate activation of jasmonate-related signaling pathway during infection.